UNDATED (CNN) - When smokers take Chantix to help kick the habit, they may face a higher risk of a heart attack or stroke.
That's according to a new study published in the Canadian Medical Association Journal.
Researchers say those who used Chantix had a higher risk of a serious cardiovascular event.
Pfizer makes the drug.
According to the New York Times, Pfizer said the study was too limited to draw conclusions about the risks.